The present invention pertains to mass production of electronic control units for electronic engine control systems and is concerned specifically with a control system having a central microprocessor.
The application of electronic controls to engine control systems accomplishes substantial improvements in engine performance. An outstanding example is the Chrysler electronic lean burn engine which monitors, via input sensors, various engine operating conditions to precisely control the timing of spark ignition. This remarkable engine achieves reduced exhaust emissions and improved fuel economy without the use of other devices (such as catalytic converters, exhaust gas recirculation) which had heretofore been required on internal combustion engines to meet Federal emission standards and which lowered fuel economy. The Chrysler electronic lean burn engine, as currently manufactured and sold by Chrysler Corporation, utilizes several analog sensors and analog circuits for converting the sensor information into analog electrical signals utilized in controlling spark timing.
The desirability of utilizing digital, as opposed to analog circuits, has heretofore been recognized in engine control systems. In particular, recent advances in microprocessor technology render the incorporation of a central digital microprocessor in an engine control system especially advantageous. In a system embodying such a device, the microprocessor carries out calculations utilized in controlling an event associated with operation of the engine, the calculations being established according to a program electronically contained in program circuitry operatively associated with the central microprocessor.
The present invention is concerned with a novel implementation of a microprocessor engine control system whereby manufacturing complexities, associated with mass production of such systems, are considerably simplified. The present invention envisions the fabrication of a basic electronic control unit containing the microprocessor engine control circuitry at an electronics manufacturing plant. The electronic control unit, at the time of shipment from the electronics manufacturing plant, has the potential for use with any of various different engine models, each having its own unique requirements for an electronic control unit. When either the engine manufacturing plant or the vehicle assembly plant determine on what model engine a given electronic control unit will be used, that control unit is electronically tailored for use with the given engine. Therefore, only one basic electronic control unit need be manufactured by the electronics manufacturing plant and stocked in a subsequent facility (such as an engine plant, assembly plant, or parts supply depot); yet the unique requirements of different engines can be readily accommodated.
The foregoing features, advantages, and benefits of the present invention, along with additional ones, will be seen in the ensuing description and claims which are to be considered in conjunction with accompanying drawings.